Roofing battens are used widely in securing flexible membranes to underlying materials. Mechanical fasteners, such as roofing screws, are passed through the battens, which may be pre-punched with holes to accommodate such fasteners. Typically, roofing battens comprise metal, wooden, or polymeric strips.
A polymeric material having particular utility in making a roofing batten is disclosed in Kish et al. U.S. Pat. No. 4,963,430. As disclosed therein, the polymeric material comprises a major amount of poly(ethylene terephthalate) and a minor amount of at least one polyolefin, such as polypropylene. As disclosed therein, such material can be substantially mono-axially oriented so as to have a tensile strength of at least about 25,000 psi in the oriented direction.
Other roofing battens made from polymeric materials are disclosed in Russell et al. U.S. Pat. No. 4,718,211 and in Schauffele U.S. Pat. No. 4,445,306. One possible arrangement of roofing battens on a roof is disclosed in Kelly U.S. Pat. No. 4,736,562.
It is disclosed in the copending patent application (Hasan et al. U.S. Ser. No. 07/294,324 filed Jan. 6, 1989, now abandoned) noted above that, as compared to a roofing batten having a single ply, a roofing batten having two plies with a combined thickness equal to the thickness of the single ply provides increased pull-through resistance when used with mechanical fasteners.
Heretofore, for purposes disclosed in the copending application noted above, it has been preferred to make a roofing batten with two plies, in one piece, from a wide strip by folding such strip longitudinally and using an adhesive to bond half portions of such strip to each other. It would be highly desirable to eliminate such strip-folding and adhesive-bonding steps.
A need has been created, to which this invention is addressed, for a better method of manufacturing a roofing batten with two plies.